Bleed-off orifice for evaporative coolers



nite States BLEED-OFF ORIFICE FOR EVAPORATIVE COOLERS This invention concerns bleed oif devices for use on evaporative coolers.

The devices attain their greatest usefulness in evaporative coolers having cases including a water sump in the bottom, evaporating pads extending above the sump, a power driven circulating pump drawing water from the sump and forcing it through an outlet pipe and a distribution head in the upper part of the case to the tops of the evaporation pads, and a constant level fresh water inlet float valve maintaining water at a predetermined level in the sump.

During operation, unless a predetermined amount of water is drawn or bled ofi from the system, soluble salts in the circulating water become concentrated and tend to deposit or crystallize out on the evaporating pads. This renders them inefficient or eventually useless.

Furthermore, in evaporative coolers having circulating pumps which pump water from a sump in the bottom of the case to the top of the pads and wherein fresh water is added by means of a constant level float valve when evaporation in the pads removes or consumes water in the sump below a predetermined level, the water circulated from the sump, through the pads, and back to the sump becomes charged with soluble salts, and insoluble dirt particles, and these substances tend to eventually clog up the evaporating pads and render them inefficient, or even ineffective.

To dispose of some of the water in the sump, independently of evaporation, and thus cause fresh water to enter the sump through the float valve, a predetermined amount of water is removed, or bled oil from the circulating water during operation of the cooler. While it is possible to allow a predetermined amount of water to escape from any place along the pipe extending from the pump to the water distribution head in the top of the cooler case, it has been found to be more desirable to bleed oil? the water from a position near the outlet of the pump where the pressure and velocity is the greatest, as shown in the pending application of Adam D. Goettl, Serial No. 528,204 filed August 15, 1955, now abandoned. In all cases it is important that the bleed 01f orifice, when once determined, shall be kept open and operative.

In view of the foregoing one of the objects of our invention is to provide a bleed ofi device which has an orifice of definite size, which is protected from clogging by dirt or undissolved solids in the circulating water, and from clogging by evaporation of dissolved solids at the orifice outlet.

Another object is to provide an orifice tip enclosed in a case containing non-deteriorating fibrous filtering material and which has a means for attaching to the bleed off pipe of a pump circulating system.

Another object is to provide a case as above stated and an orifice wherein means are provided to prevent evaporation of water around the outside of the orifice such as would tend to deposit salts from the circulating water around the orifice exit.

atent O Still another object is to provide a combined orifice and filter which is easily attached to the bleed ofi pipe of a circulating system of an evaporative cooler which will maintain a constant rate of bleed off and will not clog up or lime up during continuous operation.

Still another object is to provide a device, as above described, which may be easily and economically made and easily installed, and which is simple and rugged in construction.

We attain the foregoing objects by means of the device, construction, parts and combination of parts illustrated in the accompanying drawing in which Figure 1 is a side elevation of our improved bleed off device shown attached to the bleed 01f fitting of a circulating pump;

Figure 2 is a side elevation of the bleed ofl? device shown partially in mid-section and drawn on an enlarged scale;

Figure 3 is a side elevation of a slightly modified form of bleed oif device with portions sectioned off to show inner construction and drawn on an enlarged scale.

Similar numerals refer to similar parts in the several views.

The body 2 of the bleed ofi device consists of a metal cylinder 3 closed by a rubber plug 4 at the top which has a central opening for admitting the bleed ofl? pipe 5, water tight.

At the bottom of cylinder 3 there are threads onto which a bushing 7 is screwed. The outside of this bushing has a larger thread 8 which receives a standard hose coupling 9 to which drain hose 10 is connected.

Within body cylinder 3 there is a filter pad 12 composed of glass wool or other similar inorganic noncorrosive substance. At the bottom of the cylinder there is a trap generally indicated by numeral 14. This trap consists of an inverted cup portion 15 which provides an annular chamber 16 opening downward into a second concentric annular chamber 17 surrounding a centrally positioned vertical tube 18. Water descending through the filter 12 enters through the trap through the outer annular chamber 16 and must then descend to the bottom of the annular recess 26 before it ascends through chamber 17 to the top edge 19 of tube 18. Tube 18 is attached at its bottom to and supported by a diaphragm 20 which has a central indentation 21 around which the lower edge of tube 18 is aflixed, and a central orifice opening 23. The orifice opening determines the amount of water that will flow through the bleed off pipe 5 into filter 12. The diameter of the orifice hole is accurately gauged for this purpose.

.Any dirt that may be forced by the pump 25 through the pipe 5 will, in all probability, be stopped in filter 12. Should any dirt go further it will be caught in trap 14 and deposited in the annular recess 26 above diaphragm 20. Therefore the tube 18 will be maintained clear of all obstructing particles and the orifice will be always open and operative.

Since the circulating water is apt to become heavily charged with salts due to evaporation and concentration, it is possible that the lower face of diaphragm 20 may be coated with salts. This coating may become so heavy as to partially, or even wholly, obstruct the orifice 23. In order to prevent this we provide a shield plug 30 which is threaded into the lower end of bushing 7 and which has a number of annularly arranged outlet holes 31 spaced somewhat from its center. A centrally positioned cavity 32 is formed on its top face to provide a space between the bottom of the indentation 21, in diaphragm 18, and the top face of plug 30. The space between the diaphragm and the top of the plug forms a lower trap 33 when holding water or a shielded chamber when dry. When this trap is dry, there will be no appreciable evaporation on the lower face of indentation '20. On the other hand the outlet holes 31 in the plug 30 are adequately large so that' they will not be stoppedup by 'crusts'formed'by the evaporation of water carryinglime or salt solutions.

In the alternative form of the device shown in Figure '3 the trap 14 is eliminated and-a screen 40 is used to hold material of filter 12 in place. This screen arrests any particles not able to go through its mesh. There is a cavity 42 below this screen and this is closed at the bottom by a disk 43 which has a raised central portion provided with orifice 44. The plug 46 holds the orifice disk in place and is provided with a centrally disposed cavity 47 which is opened by the radial grooves 49 leading to the annularly arranged exit holes 48. The cavity 47 shields the orifice exit from excessive evaporation of water carrying dissolved salts likely to form crusts around the exit.

In all forms we provide the comparatively small, but eificient filter case 3 with a resilient, removable attaching bushing 4, and a removable orifice diaphragm 20 or disk 43. In either case a recess or cavity is provided ahead of the orifice opening through which the water from pump 25 passes at low velocity and with minimum turbulence so that small particles of dirt not caught by the filter will not lodge in the orifice. Any such particles will be caught either in the annular recess 26 (Figure 2) or around the outer portion of the bottom of cavity 42.

In use, after connecting the pipe 5 as above explained, the body 3 is supported by bracket 50, and the bushing 8 is coupled by fitting 9 to any convenient drain line 10.

It is to be noted that, in many regions of Southwestern United States, where evaporative aircoolers are used, the waters commonly available are usually charged with alkali salts and lime compounds. Shielding of the orifice outlet is, therefore, important. In this respect plug 30 or 46 must be removable, as shown, and the exit outlets 31 and 48 large in proportion to the size of the orifice in each case. The orifice controls the amount of circulated water bled OE, and its size is therefore critical to each installation. The device, here disclosed, keeps the orifice open and operative and renders operation of coolers of these types efiicient and foolproof. Enough fresh water is added to prevent the liming up" of the evaporative pads.

Where installed as shown in Figure 1 the drain hose or pipe 10 may lead to a sewer vent, or to a sewer drain. In such case, the form of the device, particularly the form shown in Figure 2, will act as a trap to prevent entrance of foul gases into the air cooler through the drain, as well as an efiicient bleed off orifice. Where coolers are equipped with spill over bleed oft devices, which drain into the sewer vents, there is always a problem of eliminating foul gases which enter the coolers. By using a high pressure bleed off, and the device herein disclosed, these problems are solved.

We claim:

A water bleed-off control device for attachment to a bleed-oft pipe of an evaporative cooler of the type employing circulating Water comprising a cylindrical body, a resilient plug closing one end of said body and having a bore therein for engagement over the bleed-off pipe, a fibrous filter pad positioned in said body adjacent said plug, a diaphragm engaged against the opposite end of said body, detachable means securing said diaphragm to said body, said diaphragm having a central orifice formed therein, a tube having one end secured to said diaphragm in surrounding relation to said orifice and extending toward said filter pad, an inverted cup portion encompassing the opposite end of said tube and spaced therefrom, said tube and said inverted cup portion forming a trap for retaining particles to prevent their lodging in said orifice, and a shield plug supported in said detachable means in spaced relation to said diaphragm shielding said orifice from air currents and forming a shielded chamber therebetween, said shield plug having a plurality of water outlet holes formed therein of a size larger than said orifice.

References Cited in the file of this patent UNITED STATES PATENTS 1,229,011 Amsbary et a1 June 5, 1917 1,230,024 Pritchard June 12, 1917 1,237,738 Allen Aug. 21, 1917 1,975,920 Bijur Oct. 9, 1934 2,139,659 Bijur Dec. 13, 1938 2,368,035 Moore Jan. 23, 1945 a, .t. .c 

